[PATCH 03/18] mac80211: properly handle A-MSDUs that start with an RFC 1042 header
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2021-05-11 18:03:18
Also in:
stable
Subsystem:
802.11 (including cfg80211/nl80211), mac80211, the rest · Maintainers:
Johannes Berg, Linus Torvalds
From: Mathy Vanhoef <redacted> Properly parse A-MSDUs whose first 6 bytes happen to equal a rfc1042 header. This can occur in practice when the destination MAC address equals AA:AA:03:00:00:00. More importantly, this simplifies the next patch to mitigate A-MSDU injection attacks. Cc: stable@vger.kernel.org Signed-off-by: Mathy Vanhoef <redacted> Signed-off-by: Johannes Berg <redacted> --- include/net/cfg80211.h | 4 ++-- net/mac80211/rx.c | 2 +- net/wireless/util.c | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 5224f885a99a..58c2cd417e89 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h@@ -5760,7 +5760,7 @@ unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr); */ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, const u8 *addr, enum nl80211_iftype iftype, - u8 data_offset); + u8 data_offset, bool is_amsdu); /** * ieee80211_data_to_8023 - convert an 802.11 data frame to 802.3
@@ -5772,7 +5772,7 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, static inline int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr, enum nl80211_iftype iftype) { - return ieee80211_data_to_8023_exthdr(skb, NULL, addr, iftype, 0); + return ieee80211_data_to_8023_exthdr(skb, NULL, addr, iftype, 0, false); } /**
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 531232b91bc4..f14d32a5001d 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c@@ -2682,7 +2682,7 @@ __ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx, u8 data_offset) if (ieee80211_data_to_8023_exthdr(skb, ðhdr, rx->sdata->vif.addr, rx->sdata->vif.type, - data_offset)) + data_offset, true)) return RX_DROP_UNUSABLE; ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 382c5262d997..39966a873e40 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c@@ -542,7 +542,7 @@ EXPORT_SYMBOL(ieee80211_get_mesh_hdrlen); int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, const u8 *addr, enum nl80211_iftype iftype, - u8 data_offset) + u8 data_offset, bool is_amsdu) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct {
@@ -629,7 +629,7 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, skb_copy_bits(skb, hdrlen, &payload, sizeof(payload)); tmp.h_proto = payload.proto; - if (likely((ether_addr_equal(payload.hdr, rfc1042_header) && + if (likely((!is_amsdu && ether_addr_equal(payload.hdr, rfc1042_header) && tmp.h_proto != htons(ETH_P_AARP) && tmp.h_proto != htons(ETH_P_IPX)) || ether_addr_equal(payload.hdr, bridge_tunnel_header)))
--
2.30.2